#! /usr/bin/perl

$\="\n";

$kaku = 'png';
$dirname = "doc3s";
opendir DIR ,"$dirname";
@dir = readdir DIR;

foreach $file (@dir){
    
    if ($file=~ /\s*(\d+).$kaku/){
	$1+0;
	$filenum = sprintf ("%03d",$1);
	$newfile = "$filenum".".$kaku";
	rename $file, $newfile;
#		print "$newfile";
    }
}
closedir DIR;